py23 import in all nontrivial source files and unused import cleanup
diff --git a/Lib/fontTools/misc/xmlWriter.py b/Lib/fontTools/misc/xmlWriter.py
index 48372ea..f59e74c 100644
--- a/Lib/fontTools/misc/xmlWriter.py
+++ b/Lib/fontTools/misc/xmlWriter.py
@@ -2,7 +2,7 @@
 
 import string
 import struct
-import os
+from .py23 import *
 
 INDENT = "  "